text: As mentioned previously, the relative bonding between Ni atoms in (FeNi) clusters is weak and the stability of these clusters could be enhanced by increasing the number of Fe–Fe and Fe–Ni bonds. One measure of stability in Fe–Ni clusters is the binding energy, or how much energy is required to break the bonds between two atoms. The larger the binding energy, the stronger the bond. Binding energies of FeNi clusters are found to generally decrease by successive substitutions of Ni atoms for Fe atoms.
  The average magnetic moment (μ) increases in a Fe–Ni cluster through the replacement of more and more Fe atoms. This is due to fact that magnetic moments of Fe atom/ Fe bulk are more than that of Ni atom/ Ni bulk values. The local magnetic moment of Ni (μ) decreases by a proportional increase of Fe atoms. This is due to charge transfer from nickels 4s orbital and iron atoms to nickels 3d orbitals.
  Below is a table of the bond length (R, in Å), binding energy (E, in eV), and magnetic moment (M, in μ) of the small clusters Fe, Ni, and FeNi from two authors. Notice how both authors show that Fe has the smallest bond length, the lowest binding energy, and the largest magnetic moment of the cluster combinations.
  Below is another table of bond length (R), binding energy (E), and magnetic moment (M) of Fe–Ni clusters containing five atoms.